Bump vite and @angular-devkit/build-angular in /bytefy.webapp

Removes [vite](https://github.com/vitejs/vite/tree/HEAD/packages/vite). It's no longer used after updating ancestor dependency [@angular-devkit/build-angular](https://github.com/angular/angular-cli). These dependencies need to be updated together.


Removes `vite`

Updates `@angular-devkit/build-angular` from 19.1.4 to 20.3.6
- [Release notes](https://github.com/angular/angular-cli/releases)
- [Changelog](https://github.com/angular/angular-cli/blob/main/CHANGELOG.md)
- [Commits](https://github.com/angular/angular-cli/compare/19.1.4...20.3.6)

---
updated-dependencies:
- dependency-name: vite
  dependency-version: 
  dependency-type: indirect
- dependency-name: "@angular-devkit/build-angular"
  dependency-version: 20.3.6
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <support@github.com>

bytefy.webapp/package.json

@@ -33,7 +33,7 @@
     "zone.js": "~0.15.0"
   },
   "devDependencies": {
-    "@angular-devkit/build-angular": "^19.1.4",
+    "@angular-devkit/build-angular": "^20.3.6",
     "@angular/cli": "^19.1.4",
     "@angular/compiler-cli": "^19.1.3",
     "@types/jasmine": "~5.1.0",